1. Field of the Invention
This invention relates to a cleaning and drying system, particularly to such a system which comprises an apparatus for drying discrete objects, such as workpieces which have been mechanically shaped, e.g., by turning or stamping, and have been cleaned in a washing or degreasing system which includes a cleaning fluid circuit that comprises a cleaning fluid reservoir and a cleaning vessel, which contains a stock carrier for the objects to be cleaned, which system also includes a vacuum pump which serves to suck off cleaning fluid vapors and which is adapted to be supplied with entraining fluid consisting of the cleaning fluid from an entraining fluid reservoir by a circulating pump.
2. Description of the Prior Art
Such a system is known from U.S. Pat. No. 3,610,260. In that known system the cleaning chamber is sealed only to prevent an escape of solvent vapors. The objects which have been transported out of the cleaning chamber are dried by means of a heater in a separate drying chamber. The vapors formed by the drying operation are sucked off under a low vacuum by means of a pump so that the solvent which has been evaporated by means of the heater can be recovered. A satisfactory drying cannot be effected without a heater and additional energy is required for the heating. Besides, the drying chamber is so designed that it cannot be used to dry under a substantial vacuum.
Another known system of that kind is known from U.S. Pat. No. 4,424,633 and comprises a chamber, which is in open communication with an evaporator for the liquid and in which the objects are cleaned by solvent vapors coming from the evaporator for the solvent. The heat of condensation which is thus recovered is used to dry the objects. The contaminated solvents are drained in a liquid state. That part of the solvent which is in a gaseous state is sucked off. The vacuum pump used to suck off that gas cannot generate high vacuums for drying because the cleaning chamber cannot be sufficiently tightly sealed and cannot be disconnected from the remaining system. Besides, the vacuum pump will freely deliver the finally sucked-off vapors into the atmosphere.
In a comparable system which is known from Published German Application 33 19 094 a mechanical pump or an ejector is used to suck solvent vapors from an antechamber, which precedes the cleaning chamber. But that device is not used for drying but only to reduce the amount of vapors which escape into the atmosphere and to recover such vapors.
It is also known to use for drying any desired vacuum pump, such as a liquid ring pump (see, e.g., the German periodical vt., "Verfahrenstechnik" 15 (1981) No. 2, pages 116, 117.